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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262--, Revision: 004US
311
USB 1.1 Device Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network
Processors
8.5.10
UDC Endpoint 8 Control/Status Register
(UDCCS8)
The UDC Endpoint 8 Control Status Register contains four bits that are used to operate
Endpoint 8, an isochronous IN endpoint.
8.5.10.1
Transmit FIFO Service (TFS)
The transmit FIFO service bit is be set if one or fewer data packets remain in the
transmit FIFO. UDCCS8[TFS] is cleared when two complete data packets are in the
FIFO. A complete packet of data is signified by loading 256 bytes or by setting
UDCCS8[TSP].
8.5.10.2
Transmit Packet Complete (TPC)
The the UDC sets transmit packet complete bit when an entire packet is sent to the
host. When this bit is set, the IR8 bit in the appropriate UDC status/interrupt register is
set if transmit interrupts are enabled.
This bit can be used to validate the other status/error bits in the Endpoint 8 Control/
Status Register. The UDCCS8[TPC] bit gets cleared by writing a 1 to it. This clears the
interrupt source for the IR8 bit in the appropriate UDC status/interrupt register, but the
IR8 bit must also be cleared.
Setting this bit does not prevent the UDC from transmitting the next buffer. The UDC
issues NAK handshakes to all IN tokens if this bit is set and neither buffer has been
triggered by writing 64 bytes or setting UDCCS8[TSP].
Register
UDCCS7
Bits
Name
Description
31:8
Reserved for future use.
7
RSP
Receive short packet (read only).
1 = Short packet received and ready for reading.
6
RNE
Receive FIFO not empty (read-only).
0 = Receive FIFO empty.
1 = Receive FIFO not empty.
5
FST
Force stall (read/write).
1 = Issue STALL handshakes to OUT tokens.
4
SST
Sent stall (read/write 1 to clear).
1 = STALL handshake was sent.
3
(Reserved)
2
(Reserved). Always reads zero.
1
RPC
Receive packet complete (read/write 1 to clear).
0 = Error/status bits invalid.
1 = Receive packet has been received and error/status bits are valid.
0
RFS
Receive FIFO service (read-only).
0 = Receive FIFO has less than 1 data packet.
1 = Receive FIFO has 1 or more data packets.